Ethinyl estradiol is an artificially made form of the female hormone estrogen. It is used during hormone replacement therapy and to set right hormonal imbalances due to menopause or other conditions. Hot flushes and night sweats are some of the symptoms associated with menopause that this drug treats. Menstrual irregularities and related problems are also treated with ethinyl estradiol. Ethinyl estradiol is also used for birth control.